keychain/ot/OctagonStateMachineHelpers.m

   1 /*
   2  * Copyright (c) 2018 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #if OCTAGON
  25
  26 #import "keychain/ot/OTStates.h"
  27 #import "keychain/ot/ObjCImprovements.h"
  28 #import "keychain/ot/OTDefines.h"
  29 #import "keychain/ot/OTConstants.h"
  30 #import "keychain/categories/NSError+UsefulConstructors.h"
  31
  32 OctagonState* const OctagonStateMachineNotStarted = (OctagonState*) @"not_started";
  33 OctagonState* const OctagonStateMachineHalted = (OctagonState*) @"halted";
  34
  35 #pragma mark -- OctagonStateTransitionOperation
  36
  37 @implementation OctagonStateTransitionOperation
  38 - (instancetype)initIntending:(OctagonState*)intendedState
  39                    errorState:(OctagonState*)errorState
  40 {
  41     if((self = [super init])) {
  42         _nextState = errorState;
  43         _intendedState = intendedState;
  44     }
  45     return self;
  46 }
  47
  48 - (NSString*)description
  49 {
  50     return [NSString stringWithFormat:@"<OctagonStateTransitionOperation(%@): intended:%@ actual:%@>", self.name, self.intendedState, self.nextState];
  51 }
  52
  53 + (instancetype)named:(NSString*)name
  54             intending:(OctagonState*)intendedState
  55            errorState:(OctagonState*)errorState
  56   withBlockTakingSelf:(void(^)(OctagonStateTransitionOperation* op))block
  57 {
  58     OctagonStateTransitionOperation* op = [[self alloc] initIntending:intendedState
  59                                                            errorState:errorState];
  60     WEAKIFY(op);
  61     [op addExecutionBlock:^{
  62         STRONGIFY(op);
  63         block(op);
  64     }];
  65     op.name = name;
  66     return op;
  67 }
  68
  69 + (instancetype)named:(NSString*)name
  70              entering:(OctagonState*)intendedState
  71 {
  72     OctagonStateTransitionOperation* op = [[self alloc] initIntending:intendedState
  73                                                            errorState:intendedState];
  74     op.name = name;
  75     return op;
  76 }
  77
  78 @end
  79
  80 #pragma mark -- OctagonStateTransitionGroupOperation
  81
  82 @implementation OctagonStateTransitionGroupOperation
  83 - (instancetype)initIntending:(OctagonState*)intendedState
  84                    errorState:(OctagonState*)errorState
  85 {
  86     if((self = [super init])) {
  87         _nextState = errorState;
  88         _intendedState = intendedState;
  89     }
  90     return self;
  91 }
  92
  93 - (NSString*)description
  94 {
  95     return [NSString stringWithFormat:@"<OctagonStateTransitionGroupOperation(%@): intended:%@ actual:%@>", self.name, self.intendedState, self.nextState];
  96 }
  97
  98 + (instancetype)named:(NSString*)name
  99             intending:(OctagonState*)intendedState
 100            errorState:(OctagonState*)errorState
 101   withBlockTakingSelf:(void(^)(OctagonStateTransitionGroupOperation* op))block
 102 {
 103     OctagonStateTransitionGroupOperation* op = [[self alloc] initIntending:intendedState
 104                                                                 errorState:errorState];
 105     WEAKIFY(op);
 106     [op runBeforeGroupFinished:[NSBlockOperation blockOperationWithBlock:^{
 107         STRONGIFY(op);
 108         block(op);
 109     }]];
 110     op.name = name;
 111     return op;
 112 }
 113 @end
 114
 115 #pragma mark -- OctagonStateTransitionRequest
 116
 117 @interface OctagonStateTransitionRequest ()
 118 @property dispatch_queue_t queue;
 119 @property bool timeoutCanOccur;
 120 @end
 121
 122 @implementation OctagonStateTransitionRequest
 123
 124 - (instancetype)init:(NSString*)name
 125         sourceStates:(NSSet<OctagonState*>*)sourceStates
 126          serialQueue:(dispatch_queue_t)queue
 127              timeout:(dispatch_time_t)timeout
 128         transitionOp:(CKKSResultOperation<OctagonStateTransitionOperationProtocol>*)transitionOp
 129 {
 130     if((self = [super init])) {
 131         _name = name;
 132         _sourceStates = sourceStates;
 133         _queue = queue;
 134
 135         _timeoutCanOccur = true;
 136         _transitionOperation = transitionOp;
 137     }
 138
 139     [self timeout:timeout];
 140
 141     return self;
 142 }
 143
 144 - (NSString*)description
 145 {
 146     return [NSString stringWithFormat:@"<OctagonStateTransitionRequest: %@ %@ sources:%d>", self.name, self.transitionOperation, (unsigned int)[self.sourceStates count]];
 147 }
 148
 149 - (CKKSResultOperation<OctagonStateTransitionOperationProtocol>* _Nullable)_onqueueStart
 150 {
 151     dispatch_assert_queue(self.queue);
 152
 153     if(self.timeoutCanOccur) {
 154         self.timeoutCanOccur = false;
 155         return self.transitionOperation;
 156     } else {
 157         return nil;
 158     }
 159 }
 160
 161 - (instancetype)timeout:(dispatch_time_t)timeout
 162 {
 163     WEAKIFY(self);
 164     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, timeout), self.queue, ^{
 165         STRONGIFY(self);
 166         if(self.timeoutCanOccur) {
 167             self.timeoutCanOccur = false;
 168
 169             // The operation will only realize it's finished once added to any operation queue. Fake one up.
 170             [self.transitionOperation timeout:0*NSEC_PER_SEC];
 171             [[[NSOperationQueue alloc] init] addOperation:self.transitionOperation];
 172         }
 173     });
 174
 175     return self;
 176 }
 177
 178 @end
 179
 180 #endif // OCTAGON